In the state of the art, an installation is already known for fabricating a mass of rubber, which installation comprises a vessel for compounding the mass of rubber.
The vessel includes a vessel-loading opening, an outlet opening for the mass of rubber, and a gate for closing the outlet opening. The gate is pivotable about gate axis between a position in which it closes the outlet opening and a position in which it disengages said opening.
The vessel also has two compounding rotors that are rotatable about axes that are substantially parallel to the gate axis.
The gate presents a so-called internal surface that is generated by generator lines extending substantially parallel to the axes of the rotors. As a general rule, the gate axis is also parallel to the axis of the rotors. During compounding, the rubber is homogenized, in particular under the effect of the stresses exerted on the rubber as it flows between the rotors and the internal surface of the gate.
Nevertheless, with certain rubber formulations, the rubber adheres to the internal surface of the gate in such a manner that, when the gate is open, a residue of rubber adheres to the internal surface, and that, when the gate is closed, this residue of rubber is returned into the vessel.
Unfortunately, the formulation of the rubber that is subsequently compounded in the vessel need not necessarily be the same as that previously compounded in the vessel, so returning a residue of rubber into the vessel can modify the formulation of the rubber that is to be compounded, which it is desirable to avoid in order to have control over the quality of the formulation. In addition, the residue can also prevent the gate from closing correctly, and that also ought to be avoided.
Provision is thus generally made, when the gate of the vessel is open, for an operator to clean the internal surface of the gate manually with the help of a scraper. This manual cleaning is time-consuming and requires the gate to be kept in its open position throughout the time required for cleaning it, thereby disturbing rubber production rates. Furthermore, the presence of an operator close to the vessel requires safety measures to be taken that consist in temporarily deactivating at least a portion of the installation, thereby further disturbing production rates.